如果你過量睡眠 則要小心中風大綱

Sleeping more than eight hours a day is associated with a higher risk for stroke, a new study has found.

一項新研究發現，每天睡眠超過八小時與更大中風風險有關聯。

Researchers studied 9,692 people, ages 42 to 81, who had never had a stroke. The study tracked how many hours a night the people slept at the beginning of the study and how much nightly sleep they were getting four years later. Over the 10-year study, 346 of the study subjects suffered strokes.

研究對象爲9692名42歲至81歲的人，研究開始前他們從未發生過中風。研究人員記錄了這些人在研究開始時及四年後每晚的睡眠時間。在十年的研究中，有346名研究對象中風。

After controlling for more than a dozen other health and behavioral variables, the researchers found that people who slept more than eight hours a day were 46 percent more likely to have had a stroke than those who slept six to eight hours.

在控制了十多項其他健康和行爲變量之後，研究者們發現，每晚睡眠超過八小時的人比睡六至八小時的人患中風的可能性高46%。

The study, published online last week in Neurology, also found that the risk of stroke was higher among people who reported that their need for sleep had increased over the study period.

這項研究上週發表在《神經學》週刊(Neurology)的網站上。研究還發現，在研究過程中，自稱睡眠需求增大的人中風的風險更大。

The authors caution that the data on sleep duration depended on self-reports, which can be unreliable. In addition, the study identified an association between sleep and stroke risk, rather than cause and effect. Sleeping more may be an early symptom of disease that leads to stroke, rather than a cause.

作者們警告說，睡眠時間數據基於研究對象的自我報告，也許不可靠。另外，這項研究只是表明睡眠和中風風險之間存在聯繫，並不是存在因果關係。睡得更多可能是導致中風的疾病的早期徵兆，而非中風起因。

“It could be that there’s already something happening in the brain that precedes the stroke risk and of which excessive sleep is an early sign,” said the lead author, Yue Leng, a doctoral candidate at the University of Cambridge.

“可能在中風風險出現前，大腦已經發生了某種變化，過量睡眠是其早期跡象之一，”這項研究的主要作者、劍橋大學博士研究生嶽倫（音譯）說。

In any case, she added, “we don’t have enough evidence to apply this in clinical settings. We don’t want people to think if they sleep longer it will necessarily lead to stroke.”

她補充說，不管怎樣，“我們沒有足夠的證據把研究結果用到臨牀上。我們不想讓人們認爲，睡得更久一定會導致中風。”